1. Field of the Invention
The present invention relates generally to an implement wing weight transfer apparatus.
2. Description of the Background Art
Agricultural equipment includes many types of implements. One such implement is a tillage implement used to till the soil to kill weeds and any unwanted growing plants. Tillage implements generally work on the principle of killing plants by turning over a top layer of soil or by cutting or damaging the root systems of plants below the surface of the soil.
Many types of tillage equipment exist, and vary according to soil type, plant type, terrain, crop type, and farmer preference. One variation in tillage implements is size. Farms (and therefore field size) over the years have shown a trend of steady increase in size due to the economies of scale. Therefore, implement sizes have correspondingly increased.
Increased implement size is not unbounded, however, as most implements are still transported between fields via roads and are therefore limited in size by a need to be conveniently and safely transported. In a transport mode, implements typically fold up to present a relatively small span, and unfold for an operational mode. Typically one or more pair of panels or wings are hinged to a center frame and hitch, and rotate upwardly and inwardly to a transport position. As a result, implements in a transport position may present a span of approximately one third of an operational span.
Commonly, the folding and unfolding actions are performed by actuators such as hydraulic cylinders. The wings are hinged to the frame and may be folded in numerous ways. In an operational mode, the wings are substantially collinear to and level with the frame, so that tillage tools suspended below the frame are at a substantially even height (or depth). However, the frame portion (the central structure) is generally heavier in construction than the wings and usually includes a hitch, and may include auxiliary devices such as a fertilizer tank, for example. As a result, the frame portion is heavier than the wings. Consequently, more load is placed on the tillage tools suspended below the frame, and therefore the wings may encounter greater problems in holding the tillage tools in the soil.
Related art implements solve this problem by maintaining a constant hydraulic pressure on the cylinders used to fold the wings in order to keep a down pressure on the wings. A second method uses a constant hydraulic pressure to maintain a force on an elastic means (i.e., spring) which maintains a force on the wings.
However, the related art solution presents several drawbacks. A constant hydraulic pressure tends to hold the wings in a substantially fixed position with respect to the frame. This does not accommodate uneven terrain, and in locations where the terrain under a wing is lower than terrain under the frame, the tillage tools of the wing may ride partially or completely out of the soil. Second, the maintenance of a hydraulic pressure to maintain a force on an elastic means places additional strain on the implement hydraulic system (i.e., hoses, seals, pump, etc.).
There remains a need in the art, therefore, for an improved implement wing weight transfer apparatus.